1. Field of the Invention
This invention relates to methods and apparatus for closing of bag mouths and is particularly although not exclusively applicable to closure of bags for irregular size produce such as potatoes and the like.
2. Description of the Prior Art
The supply of produce and materials in plastic bags or sachets which are closed by heat sealing or separate tape or wire closures have become commonplace. One method known as "form filling" comprises forming a tube of plastic material containing the relevant produce and heat sealing the tube at spaced intervals along the tube and severing the tube within the width of each heat seal to produce individual sachets or bags. This system is primarily used for forming sachets to contain liquids and by severing the tube at equally spaced locations along the tube, sachets containing substantially the same volumes of liquid are formed. The system is not however suitable for forming sachets or bags of material containing equal weights of discrete elements or particles such as arises in the case of supply fresh produce e.g. potatoes and the like. Conventionally bags for fresh produce and the like are individually filled with the appropriate weight of produce and the open mouth of the bag is individually closed. Such closure is normally by means of adhesive tape or wire tether although attempts have been made to heat seal the open ends of such bags. These attempts have met with little success because of the difficulty of supporting the mouth of the bag containing a considerable weight of produce whilst performing the heat seal.
The object of this invention is to provide a method and apparatus for closing the mouth of a heat sealable bag containing a weight of produce.